[HN Gopher] Rapid Prototyping with a $100 Inkjet Printer
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Rapid Prototyping with a $100 Inkjet Printer
Author : SG16
Score : 87 points
Date : 2021-05-23 12:13 UTC (10 hours ago)
(HTM) web link (ygoliya.medium.com)
(TXT) w3m dump (ygoliya.medium.com)
| 34679 wrote:
| >treating the silver ink on a hot plate at 100-120C produces
| acceptably conductive patterns
|
| Therein lies the rub:
|
| >the ideal resistivity of the silver ink traces would be less
| than 5 times that of bulk silver.
|
| >The ideal resistivities were not met, and the resistivity of the
| sample ink traces ranged from five to ten times the bulk
| resistivity.
|
| https://digitalcommons.calpoly.edu/matesp/162/
| kennywinker wrote:
| Could you explain this a bit more - I think I don't quite know
| enough about electronics to follow the criticism.
|
| Are you saying the traces are too resistive, or not resistive
| enough? How would that manifest - i.e. I see working circuits
| on the video, but are there classes of circuits that this would
| not work for?
| wiml wrote:
| Too resistive, or at least, higher than what they were aiming
| for.
|
| You can compensate by making traces wider to get a lower
| resistance from the same resistivity, or by running circuits
| slower (digital circuit speed is often limited by the RC time
| constant where C is parasitic capacitance of an input
| somewhere -- a higher-resistance trace takes longer to charge
| up the input gate capacitance). How hard it is to adjust for
| the higher resistivity will depend on the circuit, of course.
| KMnO4 wrote:
| Too resistive. Copper, silver, and gold are used because they
| have very low resistance. Having high resistance in the
| traces makes anything more complex than a few low speed
| components not practical.
| zbrozek wrote:
| There's a ton of stuff I make (especially for hobby
| projects) where I'm pretty sure it wouldn't really matter.
| I'd love to fidget with stuff like this, especially since I
| just acquired a wide-format inkjet printer.
| [deleted]
| jedimastert wrote:
| The "Show HN" tag is usually reserved for shipped products
| created by the original poster.
| tomcooks wrote:
| While the idea is amazing, I can't help but think about the
| environment. Until I'm not good enough at electronics and
| prototyping I think it's cheaper and safer for the environment if
| I experiment with a breadboard
| _Microft wrote:
| That's cool. Punch holes in these printouts, glue different
| layers together, add some extra ink into the holes for conductive
| connections between layers ("vias" [0]) and you can make multi-
| layer boards easily.
|
| [0] https://en.wikipedia.org/wiki/Via_(electronics)
| cushychicken wrote:
| Wonder how impedance control is with paper in lieu of FR-4.
| xondono wrote:
| Probably quite poor.
|
| FR4 boards are built with woven fibers, and you can get
| measurable differences depending on how tight the weave
| pattern is, or the angle of your transmission line relative
| to the weave pattern. Given that paper is not woven, I'd
| expect a lot more dispersion than on cheap PCBs.
|
| That said, with a good enough process able to press the paper
| + resin stack reliably, you could possibly get something
| usable.
| dhdc wrote:
| Probably non-existent since the thickness of insulation layer
| isn't controlled.
|
| Surprisingly, silicone rubber has a dielectric constant
| between 2 and 4 [1], which is pretty close to FR-4's 4.4. So
| maybe it isn't impossible?
|
| [1]https://res.mdpi.com/d_attachment/polymers/polymers-09-005
| 33...
| kqr2 wrote:
| Any more details on cost effectiveness? In this case the printer
| isn't the main cost but the ink.
|
| https://store.novacentrix.com/category-s/1836.htm
| pvitz wrote:
| I would be also very interested in the costs. It certainly
| saves some time, but how does it compare to etching your PCBs
| at home?
| opencl wrote:
| The cost is probably not that bad on a per-unit basis, a 50mL
| seems like it should last for a pretty large number of PCBs.
| The problem is that the resulting PCBs are almost completely
| useless because you can't solder anything to them without
| melting the substrate.
|
| The ink that works with standard inkjet printers just doesn't
| stick to materials like FR4 or kapton. There are specialized
| machines for printing conductive ink onto usable PCB substrates
| either with an extruder or screenprinting but they are at a
| minimum several thousand dollars and have extremely expensive
| consumables.
| jandrese wrote:
| That explains why all of their examples are things like
| temperature sensors, humidity sensors, or antennas. I guess
| you stick wires on the paper using some sort of conductive
| glue?
| 1MachineElf wrote:
| I wonder if circuits printed on paper would yield themselves to
| the same specialized applications as flexible PCBs.
|
| For example, there are many variations of custom-made Dactyl
| keyboards, most of which require hand-wiring to accommodate for
| the curved shape of the design:
| https://github.com/adereth/dactyl-keyboard
|
| Innovative designers have come up with alternatives that rely of
| flexible PCBs. The most recent example I recall is the Bastyl
| keyboard:
| https://www.reddit.com/r/mechmarket/comments/jvacs6/gb_basty...
|
| I don't know how to even begin prototyping with flex PCBs, but
| that barrier to entry may be lessened with paper circuits like
| these.
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(page generated 2021-05-23 23:01 UTC)